@article{DAN_1972_207_4_a12,
     author = {L. B. Grigoryeva and V. D. Zakharov},
     title = {Recurrent curvature spaces in the general relativity theory},
     journal = {Doklady Akademii Nauk},
     pages = {814--816},
     publisher = {mathdoc},
     volume = {207},
     number = {4},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1972_207_4_a12/}
}